Royals pitchers Ervin Santana and Bruce Chen officially became free agents at 8 a.m. Thursday as Major League Baseball entered its offseason schedule one day after the Boston Red Sox won the World Series.

Royals pitchers Ervin Santana and Bruce Chen officially became free agents at 8 a.m. Thursday as Major League Baseball entered its off-season schedule one day after the Boston Red Sox won the World Series.

Free agency started automatically for all players who are not under contract for next season and who have at least six full years of major-league service.

The Royals, for all practical purposes, have only two such players, Santana and Chen, but both were members of a rotation that helped the club lead the American League in earned-run average for the first time since 1986.

Technically, suspended infielder Miguel Tejada and first baseman Carlos Pena are also free agents following their reinstatements on Thursday.

Tejada had been on the restricted list and still has 64 games remaining on his 105-game suspension, announced in August, for violating baseball’s drug policy.

Pena was on the 60-day disabled list following a mid-September emergency appendectomy. In all, the union says 147 players are qualified for free agency.

General manager Dayton Moore has made it clear his top off-season priority is to maintain a strong rotation either by retaining Santana and/or Chen or finding viable replacements.

“We’re going to do the best we can,” Moore said, “to put as many quality guys as we can in that rotation. We feel like we’ve got a lot of really good internal options.

“We’re really proud of what Ervin did for us, and we’re going to be excited to see if we can get him under contract. But we’ve got to prepare for all different scenarios. That’s what Erv is doing as well.”

Santana appears open to remaining with the Royals after compiling a 3.24 ERA in 32 starts, which belied a 9-10 record, after arriving exactly a year ago — Halloween 2012 — in a trade from the Los Angeles Angels.

“I like it (here) a lot,” he said late in the season. “Great people. Great teammates. The training staff is incredible. It’s a good town for baseball. There’s not much to do except focus on baseball. That’s very good.”

The Royals and Chen have also each expressed interest in a new deal.

So what happens now?

Clubs have until 4 p.m. Monday to make qualifying offers to their free agents in order to receive a draft pick as compensation if the player signs with another club.

There is a catch, although it doesn’t apply to Santana or Chen. Players who were traded during the just-completed season are not eligible to receive qualifying offers.

Those offers are uniform for all players: a one-year contract for approximately $14.1 million — or the average of the top 125 salaries in baseball for the 2013 season.

Moore said Santana, who made $13 million in 2013, will receive a qualifying offer. Chen, who made $4.5 million, will not.

Players who receive qualifying offers have until 4 p.m. on Nov. 11 to accept the offer. If the player accepts the offer, he becomes a signed player and ceases to be a free agent.

The qualifying-offer system started last year under terms of baseball’s new labor agreement. All seven players who received offers chose to reject them in hopes of signing a more lucrative multi-year deal.

Players can reject a qualifying offer and continue to negotiate with their former club. In fact, their former club enjoys a negotiating advantage in that it wouldn’t be required to surrender a draft pick if it signs the player.

Clubs that sign a player from another club who received a qualifying offer forfeit their first-round pick (and the signing bonus-pool allotment) in next June’s draft unless they have one of the first 11 selections.

Those clubs with one of the first 11 picks forfeit their second-round pick. The club losing the player, in either case, receives a pick in a supplemental round between the first and second rounds.

Thursday also marked the start of a five-day quiet period that concludes at 10:59 p.m. Monday. Free agents can talk with other clubs but are prohibited from negotiating financial terms.

Free agents are allowed to negotiate and sign with their former clubs during the quiet period.